Back to your chain and cog width, you're probably better off with 3/32" than 1/8". You existing chainring is a 3/32". You can find a gazillion cogs in both widths, but your chain selection (and value, IMO) is better for 3/32". If you're really keen on 1/8", it will work fine, but I don't see any particular advantage to going that route unless you're already contending with 1/8" track chainrings and the like.